This is a phase I pharmacokinetic (PK) study of carmustine (BCNU) & temozolomide in patients with CNS tumors. It is anticipated that 10 patients will enter this study at the UPCI. PK will be performed during the first cycle of therapy of both arms of the study at all dose levels. The primary endpoint of the study will be determination of the MTD of temozolomide plus BCNU for each schedule.